The present invention relates more particularly to a machine for packaging a product or products into a cardboard box in a boxing cycle comprising at least three successive operations for making up, filling and sealing the box, the machine comprising boxing means which are arranged along a longitudinal packaging line of the machine comprising, from the upstream end downstream, a first, making-up, station which receives a succession, at a given rate, of box blanks intended to be at least partially made up and comprising a conveyor device for successively transferring in the downstream direction in an outbound path the box which has thus been made up toward a second, filling, station at which the products are packed into the box by associated loading means able to deposit the products that are to be packaged in the box, and then on to a third, box-sealing, station at which the box is sealed before it is discharged from the machine.
Numerous packaging machines of this type for packing or boxing products, particularly prepackaged products such as tins, bottles, bags, etc., that is to say, in general, any kind of packaged goods, particularly with a view to protecting them and making them easier to transport, for example to dispatch from a production site to a sales outlet, are known.
The various types of packaging machine are conventionally configured according to the type of cardboard box used for boxing or overwrapping the products.
The term “overwrapping” defines the operation of reinforcing or protecting a group or batch(es) of prepackaged products.
Thus, a broad distinction is drawn between machines of the “boxing” type using boxes with flaps, known as “American boxes” and machines of the “overwrapper” type which use boxes of the “wrap-around” type.
Whatever the type of packaging machine, the boxing cycle generally involves at least the three operations, that is to say making up the box, filling it and sealing it. These operations are performed in succession along the packaging line thanks to a conveying device that conveys the boxes between the various stations.
For example, a conveying device comprising two chains mounted in parallel, each having dogs arranged in such a way as to restrain the bottom of the box near its four corners so that the boxes can be transferred to each of the stations in the packaging line of the machine, is known.
A lateral part of the bottom of each box is therefore in contact with a longitudinal portion of each chain lying between two successive dogs. The dogs are mounted such that they are secured to each chain and extend vertically above the chains to restrain the box longitudinally in the direction of travel, so that items can be boxed.
The endless chains are rotated by drive means, such as a motor, which are connected to two transverse axles, fitted with sprockets, arranged at each of the upstream and downstream ends of the packaging line.
However, such chain-type conveyor devices are not entirely satisfactory.
The problem is that at high operating rates, chain-type conveyor devices are generally unable to position the box blanks or boxes accurately between the dogs, and this may lead to operational incidents, particularly during filling, as a result of boxes being incorrectly restrained or positioned.
In addition, it has been found that the articulated links that make up each chain are sensitive to the various types of dirt and contaminant to which the conveyor device is exposed.
As a result, such chain-type conveyor devices are unsatisfactory in certain applications, such as in the field of cosmetic products for example, especially where such packaging machines are being required to exhibit improved reliability, improved productivity, particularly in the form of an increase in throughput, and operational flexibility so that they can, to advantage, cope with rapid changes in cardboard box format.